4.3 Factor Analysis
The five speeded cloze-elide passages, the four C-Tests, the two
multiple-choice cloze passages, and the reading comprehension passage
were subjected to principal component analysis (PCA) using SPSS version
21. Prior to performing PCA, the suitability of the data for factor
analysis was assessed. The Kaiser-Meyer-Olkin value was .95, exceeding
the recommended value of 0.60 (Kaiser, 1970, 1974) and Bartlett’s test
of Sphericity (Bartlett, 1954) reached statistical significance,
supporting the factorability of the correlation matrix. Principal
component analysis showed the presence of one component with eigenvalue
exceeding 1, explaining 72% of the variance. An inspection of the scree
plot revealed on clear break after component one which supports
extraction of one factor.